1. Field of the Invention
Embodiments relate to a method of manufacturing a semiconductor active layer, a method of manufacturing a thin film transistor using the same, and a thin film transistor including the semiconductor active layer.
2. Description of the Related Art
A semiconductor layer using amorphous silicon or polysilicon has recently been developed for use in a thin film transistor (TFT) for light emitting display devices such as organic light emitting display devices, which use organic light emitting diodes (OLEDs) to emit light.
When the semiconductor layer is formed of amorphous silicon, the semiconductor layer may exhibit low mobility. The use of such a low mobility layer as a drive circuit of a display panel that requires a fast response time may be difficult. Polysilicon may be used as the semiconductor layer to provide high mobility, but the threshold voltage of the TFT may not be uniform. Additionally, leakage current may occur in the amorphous silicon or polysilicon semiconductor layer when light, e.g., light from a backlight unit, is incident thereon.
Oxide-based semiconductors may exhibit a band gap that is higher than the light energy in a visible light region. Accordingly, an oxide-based semiconductor may exhibit little or no leakage current resulting from visible light absorption. Therefore, the use of oxide-based semiconductors, e.g., semiconductors having an indium-gallium-zinc oxide (hereinafter, “IGZO”) active layer, has been proposed as a solution to problems in the art. However, there is a need for further developments in the formation of an IGZO active layer, e.g., to provide control over the atomic composition thereof and improve the electrical characteristics of devices including the IGZO active layer.